In process automation technology, field devices are often used, which are connected with superordinated units via a field bus.
Field devices serve generally for registering and/or influencing process variables.
Examples of such field devices are fill level meters, mass flow meters, pressure and temperature measuring devices, pH-redox measuring devices, conductivity measuring devices, etc., which, as measuring devices, register the corresponding process variables fill level, flow, pressure, temperature, pH-value, and conductivity. A large number of such field devices are manufactured and sold by the firm Endress+Hauser®.
The superordinated units serve for process visualization, process control, as well as for interacting with the field devices attached to the field bus.
Examples of field bus systems are Profibus®, Foundation® Fieldbus, etc.
Via the field bus, not only measured values but also a multiplicity of different kinds of information can be exchanged between the field device and a superordinated unit. Thus, for instance, device specific information can be stored in the field device and called-up as required. Such device-specific information can include location information, start-up information, service information, etc. A storing of device-specific information in the field device is, however, only possible, once the field device has been installed on the field bus and is ready for operation. The input of this information can, on the one hand, be done at the device itself, with the help of a display and keyboard, or, on the other hand, such can be done from a superordinated unit.
As a rule, device-specific information (location information and start-up information) arises at the installation of the field device of concern. In this case, a technician must cumbersomely input this information via the keyboard at the field device or e.g. forward such to appropriate operating personnel, in the case of the superordinated unit (control room). As a rule, the devices are not yet operational at the installation, i.e. they first have to be initialized. This means, however, that the mentioned information can only be stored in the field device after a delay. Because of this delay, it becomes possible that erroneous information becomes stored in the field device.
Likewise problematic is the storing of service information, when the relevant field device is malfunctioning.
Furthermore, in the case of a device replacement, all information stored in the device is lost.